On a cool morning recently, Jay Mallin was coolly telling a reporter that the radio station for which Mallin works as news director cannot be -- heaven forfend! -- ''blamed'' for successful escapes from Cuba.

Granted, Radio Marti's weather reports, broadcast from Washington and transmitted from Florida, are more detailed than reports broadcast by Cuban government radio. Marti's long-term forecasts and information on tides are closely listened to, especially by persons -- often of military draft age -- who are considering dangerous floats to freedom on inner-tube rafts.

Granted, also, such people are especially apt to listen to Marti, the U.S. government Spanish-language station now beginning its second year of broadcasting to Cuba. But Marti is prevented by its strict charter, as well as the wisdom of its administrators, from incitements.

Mallin tolerates no name-calling. Castro is referred to "el gobernador," as the leader. Mallin has had Castro on his mind for many years.

Born in 1927 in New York into an American family with two generations of roots in Cuba, he was working for Time magazine during the revolution. During Castro's victory march to Havana in January 1959, the lead car carried Castro, the second car his security people, the third car the Time-Life contingent.

Ernesto Betancourt, Marti's director, supported the revolution in the 1950s and represented Castro's movement in Washington in 1957-1958. He left Cuba in 1960, when Castro's antidemocratic intentions became clear.

Marti's impact is measured anecdotally, but by lots of anecdotes. There are interviews with travelers from Cuba, surveys of emigrants from Cuba (often arriving through third countries), correspondence from Cuba to relatives here. Mail to and from Cuba is measured in tons. Thirty-thousand telephone calls are attempted daily from Miami, and 6,000 get through.

Castro does not attempt maximum jamming of Marti, partly because of the cost. Cuba is a mendicant nation, selling its young men as soldiers in exchange for Soviet subsidies. Jamming is expensive. The Soviet Union spends about $490 million a year to jam U.S. non-English broadcasts to the Soviet Union. Such U.S. transmissions cost just $26 million. All Soviet jamming involves 15,000 technicians at 2,000 jamming stations, costing approximately $1 billion annually.

Aside from the cost, Castro's vanity causes him to avoid full-scale jamming, which would affirm Marti's appeal. Marti, with 80 correspondents, costs just $10 million annually, less than one advanced fighter plane. Marti is a magnificently cost-effective weapon.

Cubans are ravenous for news from Angola and Ethiopia, where 400,000 Cubans (half of them civilians) have served Soviet purposes. Castro's worship of Soviet technology caused a four-day stunned silence in the Cuban press after Chernobyl. Marti instantly broadcast not only the news, but a nuclear glossary, and interviews with exiled Cuban scientists about a nuclear plant Soviet technicians are building in Cuba.

Because Cuba is governed by ''scientific socialism,'' there are, by definition, no crimes or other serious defects. However, since Marti has been broadcasting about developments in Cuba, Cuban broadcasts have been giving more attention to crimes and to such problems as AIDS (which, until recently, Cuban authorities said did not exist there).

From Marti, Cubans learned of the massacre of dozens of young people when planes and gunboats sank a pleasure boat sailing toward freedom. Marti told Cubans about the attempted kidnapping of a Cuban defector by Cuban Embassy officials in Madrid. Marti has reported the shambles of Cuba's sugar production: Cuba is reduced to buying sugar in the world market. Then it sells that, for less than it paid for it, to East bloc nations to pay for Soviet subsidies.

An especially popular program on Marti is ''Family Bridge,'' on which Cubans and Americans call Marti on an (800) number and give personal messages that are beamed to Cuba. ''Aunt Maria's operation went well, and Jose is engaged.'' But even more popular than the broadcast of jazz, ''Top 40'' rock 'n' roll and baseball is a soap opera about ''Esmerelda.''

She -- Esmerelda, that is -- is one reason Cuban broadcasting is improving. Totalitarian regimes politicize everything and extinguish the freedom not to think about politics. The growth of Marti's audience for its nonpolitical programming has forced Cuban broadcasting to lighten up. There is now more programming for the restless young and more first-run movies in prime time.

This change is a reluctant concession to consumer sovereignty. Any such acknowledgement, however small and surly, of the power and claims of popular desires subverts the central pillar of totalitarianism, the tenet that the masses should be utterly passive and plastic to the power of the state.

So the voices beamed from the studios in the building at the foot of Capitol Hill have produced in Cuba a small stirring, something like a crocus sprouting through a crack in concrete. And life, however frail, has a way of triumphing, in time, even over stone.